| 摘要 |
<p>PURPOSE:To make it possible not only to effectively reduce BOD, COD but also to remove nitrogen in sewage inexpensively and continuously in good efficiency, by skillfully combining two kinds of recirculation type filter beds which carries out nitration action and denitrification action respectively. CONSTITUTION:In an aerobic contact tank 1, sewage is recirculated between an aerating recirculation cylinder 3 arranged in said tank 1 and an aerobic contact material layer 4 provided in introduced sewage and having aerobic activated sludge deposited thereon through a sewage permeable contact material layer holder 2 horizontally provided to the lower part in the tank 1. On the other hand, in an anaerobic contact tank 8, sewage is recirculated between a recirculation cylinder 11 arranged in the hermetically closed tank 8 and an anaerobic contact material layer 12 provided in the introduced sewage and having anaerobic activated sludge deposited thereon through a sewage permeable contact material layer holder 10 horizontally provided in said hermetically closed tank 8. The tank 1 and the tank 8 are communicated to recirculate sewage between both tanks 1, 8 and the removal of the nitrogen component in the sewage is enabled by nitration and denitrification of said sewage.</p> |
